Brooks Koepka and Rory McIlroy are first and second in the world rankings respectively but the American dismissed the notion of a rivalry between the two, saying "Rory hasn't won a Major since I’ve been on the PGA Tour".
The last of McIlroy's four Major wins came at the USPGA Championship in 2014, while Koepka - on the PGA Tour since 2015 - has lifted four in the last two years.
Last month, McIlroy was named the PGA Tour Player of the Year for a third time, but he's currently secodn in the rankings, behind 29-year-old Koepka.
Speaking ahead of his defence of the CJ Cup, Koepka said: "I've been out here for, what, five years. Rory hasn’t won a Major since I’ve been on the PGA Tour. So I just don’t view it as a rivalry.
"I'm not looking at anybody behind me. I’m number one in the world. I’ve got open road in front of me I’m not looking in the rearview mirror, so I don’t see it as a rivalry.
"You know if the fans do [call it a rivalry], then that’s on them and it could be fun.
"Look I love Rory he’s a great player and he’s fun to watch, but it’s just hard to believe there’s a rivalry in golf. I just don’t see it."
In August McIlroy emphatically outduelled Koepka and Xander Schauffele with a closing four-under 66 at East Lake en route to the the Tour Championship and FedEx Cup.
McIlroy took the fight to Koepka just four weeks after being given a lesson by the American when they were paired in the final round at a World Golf Championships event in Memphis.
"Going up against the number one player in the world today, he got one over me in Memphis and I wanted to get some revenge," McIlroy said at the time.
"To play like that alongside Brooks, get the win, win the FedEx Cup, it's awesome."